Manhole covers began life as slabs of stone or pieces of wood giving access to the covered trenches that were carrying sewage. It was the Romans who were totally obsessed with sewage, drainage and manholes and today our own systems are pretty similar to these original Roman designs.
The basic design began in 3500 BC through to 1750s-1850s. During the 19thC, modern manholes and the modern manhole cover were developed.
Not a whole lot has really changed in the years between the 1870s and now relative to the philosophy of manhole design, definitions, etc.; mainly materials and installation techniques have changed. The early designers had an amazingly good sense of what was needed.
Manhole covers also act as markers or badges for streets They can reveal much about the history of of an area and the type of industries that developed there. Names of the manufacturers are cast into the exterior. The history of the city is there to see, engraved on to the covers. In London, for instance, you might find covers inscrived with the name of George Jennings, the unitary engineer who introduced the flush toilet to London at the Great Exhibition of 1851, an invention which quickly became so popular that the city’s decrepit sewer system was unable to cope and the contents were flushed into the Thames, leading to the Great Stink summer of 1858. You may find others featuring the name of the sanitary engineer Thomas Crapper, with holes to allow the gas to escape from sewers so avoiding a build-up of gas pressure and the possible explosion of an iron cover shooting through the air at great speed. This is not as uncommon as you might think and in recent years there have been flying manhole covers in New York. Ouch.
They have been described as street jewellery and there are some amazing designs around the world providing a little brightness and colour in what is otherwise a smelly, grey and drab world